Bootstrap 4 Beta

https://blog.getbootstrap.com/2017/08/10/bootstrap-4-beta/
Kudos to this blog post for linking to a video of ELO's Mr Blue
Sky. It has taken two long years to get to beta but here it is. As
the blog put it "shipping a beta means we're done breaking all your
stuff until our next major version". Nice work by the Bootstrap
team.